Whales can be found in all of the world's oceans, but the specific location depends on the species of whale. Sperm whales can be found in all of the oceans of the world, for example, with male populations found primarily in the equator and polar regions, and young whales and females located mainly in temperate regions. Blue whales live off the coast of California, migrating to Costa Rica and Mexico.
Whales are warm-blooded mammals that need to breathe air into their lungs to survive. Whales are conscious of when they need to take a breath of air and do not sleep deeply for long periods in order to break the surface of the water whenever necessary. Whales breathe through their blowholes, which are located on the tops of their heads, and which allow them to remain almost fully submerged in the water while breathing. Krill is the primary source of food for many species of whales, but they also eat a range of foods, including plankton, squid, fish and other marine mammals.
Whales have a layer of fat called blubber, which provides insulation and allows them to store energy. Female whales give birth to one calf at a time, and have a gestation period that lasts 9 to 15 months and varies with each different species of whale. Whales nurse their calves for approximately one year, which forms a strong bond between the mother and her baby.